um: Add HAVE_DEBUG_BUGVERBOSE

This option restores the DEBUG_BUGVERBOSE functionality as it was
previous to commit 9a93848f ("x86/debug: Implement __WARN() using
UD0").
Signed-off-by: NHernán Gonzalez <hernan@vanguardiasur.com.ar>
Signed-off-by: NRichard Weinberger <richard@nod.at>

arch/um/Kconfig

@@ -12,6 +12,7 @@ config UML
 	select HAVE_UID16
 	select HAVE_FUTEX_CMPXCHG if FUTEX
 	select HAVE_DEBUG_KMEMLEAK
+	select HAVE_DEBUG_BUGVERBOSE
 	select GENERIC_IRQ_SHOW
 	select GENERIC_CPU_DEVICES
 	select GENERIC_CLOCKEVENTS